Recently, a video telephone system (video chatting system) in which users can converse on the phone while seeing the faces of their partners has been generally used with convenience using a personal information processing terminal such as a PC (Personal Computer). In order to realize comfortable communication with conversation partners in the video chatting system, technologies of displaying images of the contacting partners to users as if the users were speaking to the conversation partners face-to-face have been proposed. For example, PTL 1 proposes a technology of displaying, on a display screen for a user, an image of a conversation partner in which depth of the display screen and depth of a direction of a line of sight of the user are reflected according to a change in the line of sight (a position of the eyes) of the user.